Kubernetes Cluster Federation
Kubernetes Cluster Federation (KubeFed for short) allows you to coordinate the configuration of multiple Kubernetes clusters from a single set of APIs in a hosting cluster. KubeFed aims to provide mechanisms for expressing which clusters should have their configuration managed and what that configuration should be. The mechanisms that KubeFed provides are intentionally low-level, and intended to be foundational for more complex multicluster use cases such as deploying multi-geo applications and disaster recovery.
KubeFed is currently beta.
KubeFed is configured with two types of information:
- Type configuration declares which API types KubeFed should handle
- Cluster configuration declares which clusters KubeFed should target
Propagation refers to the mechanism that distributes resources to federated clusters.
Type configuration has three fundamental concepts:
- Templates define the representation of a resource common across clusters
- Placement defines which clusters the resource is intended to appear in
- Overrides define per-cluster field-level variation to apply to the template
These three abstractions provide a concise representation of a resource intended to appear in multiple clusters. They encode the minimum information required for propagation and are well-suited to serve as the glue between any given propagation mechanism and higher-order behaviors like policy-based placement and dynamic scheduling.
These fundamental concepts provide building blocks that can be used by higher-level APIs:
- Status collects the status of resources distributed by KubeFed across all federated clusters
- Policy determines which subset of clusters a resource is allowed to be distributed to
- Scheduling refers to a decision-making capability that can decide how workloads should be spread across different clusters similar to how a human operator would
|Push propagation of arbitrary types to remote clusters||Alpha||PushReconciler||true|
|CLI utility (
|Generate KubeFed APIs without writing code||Alpha|
|Replica Scheduling Preferences||Alpha||SchedulerPreferences||true|
- Clone this repo:
git clone https://github.com/kubernetes-sigs/kubefed.git
- Start a kind cluster:
kind create cluster
- Deploy kubefed:
You now have a Kubernetes cluster with kubefed up and running. The cluster has been joined to itself and you can test federation of resources like this:
- Verify the
KubeFedClusterexists and is ready:If you're on macOS the cluster will not immediately show as ready. You need to change the API endpoint's URL first:
kubectl -n kube-federation-system get kubefedcluster
- Create a namespace to be federated:
kubectl create ns federate-me
- Tell kubefed to federate that namespace (and the resources in it):
./bin/kubefedctl federate ns federate-me
- Create a
ConfigMapto be federated:
kubectl -n federate-me create cm my-cm
- Tell kubefed to federate that
./bin/kubefedctl -n federate-me federate configmap my-cm
- Verify the
FederatedConfigMaphas been created and propagates properly:
kubectl -n federate-me describe federatedconfigmap my-cm
Take a look at our user guide if you are interested in using KubeFed.
Take a look at our development guide if you are interested in contributing.
Refer to the contributing guidelines if you would like to contribute to KubeFed.
KubeFed is sponsored by SIG Multicluster and it uses the same communication channels as SIG multicluster.
Code of Conduct
Participation in the Kubernetes community is governed by the Kubernetes Code of Conduct.